OBJECTIVE: The goal of this study was to determine the outcomes of stage IC endometrial carcinoma patients who are managed with and without adjuvant radiation therapy after comprehensive surgical staging. METHODS: Patients with FIGO stage IC adenocarcinoma of the endometrium diagnosed from 1988 to 1999 were identified from tumor registry databases at four institutions. A retrospective chart review identified 220 women who underwent comprehensive surgical staging including a total hysterectomy, bilateral salpingo-oophorectomy, pelvic/paraaortic lymphadenectomy, and peritoneal cytology. RESULTS: Of the 220 stage IC patients, 56 (25%) patients received adjuvant brachytherapy (BT), 19 (9%) received whole-pelvis radiation (WPRT), and 24 (11%) received both WPRT and BT. One hundred twenty-one patients (55%) did not receive adjuvant radiation. There were 6 recurrences (6%) in the radiated group and 14 (12%) in the observation group (P = 0.20). Seven of fourteen recurrences in the observation group were local, and all local recurrences were salvaged with radiation therapy. Two of seven distant recurrences in this group were also salvaged with surgery and chemotherapy. The overall salvage rate for the observation group was 64%. There was a statistical difference in 5-year disease-free survival between the radiated and observation groups (93% vs 75%, P = 0.013). However, the 5-year overall survival was similar in the two groups (92% vs 90%, P = 0.717). CONCLUSION: Adjuvant radiation therapy improves disease-free survival in surgical stage IC patients; however, overall survival is not improved with adjuvant radiation therapy since the majority of local recurrences in conservatively managed patients can be salvaged with radiation therapy.